Exposure to environmental toxic agents in the prenatal and/or postnatal periods may play in the acquired development of attention-deficit/hyperactivity disorder (ADHD) in groups with genetic risks. Bisphenol A (BPA) is a widely used industrial chemical with neurotoxic effects. This study examined the relationship between exposure to BPA and clinical ADHD. This cross-sectional, case-controlled clinical study compared 45 drug-naive children and adolescents with ADHD and 30 healthy controls in terms of serum BPA levels. Psychiatric comorbidities in the ADHD group were determined using the "Schedule for Affective Disorders and Schizophrenia for school-aged children, lifetime version." The Child Behavior Checklist (CBCL) was also administered to all participants. Serum BPA levels were significantly higher in the ADHD group than in the healthy control group. In addition, significant, weak positive correlation was found between BPA levels and CBCL attention and CBCL total problem scores. Our results show that BPA may be an environmental toxic agent with a potential role in the etiology of ADHD and particularly attention deficiency. Preventive interventions can be developed if this can be confirmed with longitudinal studies and repeated measurements.